Process for dyeing animal hairs with anthraquinone vat dyestuffs



i atented May 16, 1950 raocussroa DYEING ANIMAL ams WITH- ANTHRAQUINQNE VAT DYESTUFFS Arthur E- e Bids djN- IJ a iei or to Allied Chemical & Dye Corporation, New York, N. Y., a corporation of New-York No Draw ns- Arplication ugu-St 1,7, ,948

Serial No.44 ,796'

Thisinvention relates to a process for dyeing animalhairs with anthraquinone vat dyes.

The vat dyes, as is well'known, areinsoluble in water and cannot be used directly for dy ing. These dyes, however, all have the common characteristic of possessing one or more reducible I ..=0 roup ich up n rea m w t educing agents become reduced to C-OH, a form of the dye called the leuco compound. This form, is soluble in alkalis. Alkaline solutions of the leuco compounds possess a considerable ait inity" for fibres and also have the property of being readily'reoxidized to the colored compound on treatment with air'or other oxidizing agents, with formation of'the original dyestuff.

Accordingly, it has been common practice in the past to dye cellulose fibres such .as'cotton by immersing them inan alkaline dye bath of the reduced vat dye" to absorb the leuco compound,

and then removing thefibres and reoxidizingthe 'leuco compound to'formthe insoluble colorin and on the'fibres. In this way the color becomes firmly fixed; resulting in exceedingly fast dyeings.

Not only are the vat dyestuffs the fastest colors knownbut they possess as well a high deg-reeof brilliance and purity, and are available in acornplete range of shades,

'Inthe-past, however, the vat dyes have been used almostexclus'iv ely fordyeing vegetable fibres, especiallycotton,"since the alkali necessary to keep the dye in solution tends to dissolve and deteriorate animal" hairs even on short exposure .to the dye bath. Efforts have: been m-ade in the past toadapt the anthraquinone vat dyestuffs, for

use-in dyeing wool and other'ammal hairs. These efforts were unsuccessful except in a'few isolated cases such as dyestuffs of the character of diben zoyl 1,5 diamfnoanthraquinone' (Schultz 8110131132), and perhaps others, which could be maintainedin solution at relatively low alkalinity, i. e., at pHvalueswell belowi12', andeven in such cases producedonly'dull, weak shades. In the'great majority of cases it was impossible to reduce the amount ofalkali' to" a sufficient ex.-

tenttoavoi'd deterioration of the-animal fibres, as such reduction would have brought the quantity of alkali below the practically irreducible minimumof alkali necessary to keep the 'l'euco compound in solution and assure satisfactory penetrationand resulting strong dyeing of the goods. Other'in'direct efforts have taken a number of forms such asusing protective colloids, eta, which proved to be unsatisfactory because they failed to preserve the strength and soit'hand 9-Claims.

of thevat dyes to 'aniinalfibles took thefforfm of converting the dry leucocornpounds to.watersoluble forms, for example, by treatment of the leuco compound with chloro'su-lfonic acid the presence 'of atertiary base or 'by the action of an alkyl" ester of chlorosulfonic acid in the pres ence-qfa metal and a tertiary'base. These water solubilized vat dyes, while making possible the.

: use of this type of dyeson-wooLwere unsatisfac tcryfor-a number of reasons including there suiting comparatively weak and dull dyeings, as welljasfthe added greatexpense of solubilihing the-dye. Although some ofthe prior artefforts have been partially successful in adapting certain of the anthraqu-inone vat colors for use indyeing-silk, Lananimal fibre ofthe extruded type, not anammal hair, and hence more resistant to causticalk-al-i than animal hairs such-as wool), ncneofthe priorart efiorts proved successful in simultaneously achieving, with respect to animal hairs, the 1 two requirements of 1 good dyeings of (1) a aclear strongdyeing together with 1 (2) sub stantial preservation-of the strengthof the hairs dyed.

"It isan objectof my invention toprovide a process for dyeing animal: hairs with dyes or: the type orxanthraquinone vat dyes.

i'It is another object of my-invention, to pro: vide' a processtfior dyeing. animal hairs withcansthraquincne vat dyestuffs of such character that their leuco forms are substantially completely soluble innalkalis only at true pH values aboye about 1'2.

It is a'iurther-ohjeet of the. invention tozpro-e vide a process of the character describedinwhich no changes are necessary in the dyestuff itself.

It is-a still further object of the invention to provide 1a1process .of the character described in which strong, clear dyeings' are obtained. witlr no wrdue deterioration in the tensile strength ofthe dyed-hair.

Flt =is a still mrtherdobject of the invention to provide a. process: for \dyeing wool with anthrae cguinone vat dyestuffs in which-strong, clear dyeiings areobtained witlr n0? undue deterioration in the tensile strengthrof. the dyed wool.

These and other, obiectsaare accom pli'shedacecordingtozimy iniventiona wheneini animal hairsaite dyed; with anthraqulnone type vat .dyestufis in dye baths of alkalinity such: that: their true pH values lie-"between: about l2 -andabout 13-,and

contain, in additiom to the alkaline material, an excess 1 er; alkali; metal hydrosu lfite and icontrul'l'edcquantities orsalt.

Among the animal hairs adapted to be dyed according to my invention are all animal hairs of the character of fleece and fur, such as the fleece of sheep, goats, camels, etc., and also fur such as rabbit fur used in the manufacture of felt hats. The invention is primarily concerned with the coloring of hair derived from sheep, generally known as W001, in all phases of its processing, such as raw stock, top, sliver, woolen and worsted yarns, knitted, woven and felted fabrics. The present invention also deails with the dyeing of animal hairs or yarns and fabrics made therefrom which have been altered by chemical processing such as acid or alkaline chlorination, treatment with formaldehyde, strong alkalis, oxidizing agents, ethylene dibromide plus sodium hydrosulfite, and similar preliminary treatments. My process likewise is adapted to the coloring with the vat colors described, of animal hairs present in yarns or fabrics in combination with other fibres in which the animal hair constitutes the major part of the yarn or fabrics, such as, for example, 75% wool and 25% viscose, or 60% mohair and 40% cellulose acetate.

In carrying out the process of my invention, an aqueous alkaline dye bath is prepared containing an alkali, an alkali metal hydrosulfite, and a salt; and containing sufiicient alkali to keep the leuco compound substantially completely in solution. The dye bath thus prepared is substantially similar to vats used in dyeing cotton with such dyes except that (1) the quantity of hydrosulfite used is in excess of that required to keep the dyestuff in the leuco form, and (2) a quantity of salt is added, even in the dyeing of such colors which are normally dyed on cotton without salt. The salt may be either common salt such as sodium chloride or Glaubers salt, i. e. sodium sulfate, or other neutral alkali metal salt. The dye bath will thus contain the anthraquinone vat dyestuff, an excess of hydrosulfite over that required to keep the dyestuff reduced to the leuco form; an alkali such as sodium hydroxide in sufllcient concentration to keep the reduced dyestufi completely in solution, 1. e. sufiicient to produce an orange color reaction with thiazol yellow test paper, so-called Clayton yellow test paper, that is, to sure a pH value between about 12 and about 13, and in addition, quantity of salt varying according to the particular dyestuff, the weight of the wool and strength of the dyeing to be made, but which should be at least about 5 grams of salt per liter, on an anhydrous basis, preferably between about 5 and 50 grams per liter, i. e. between about .5% and 5% of salt based on the weight of the dye liquor.

In the method of m invention a number of critical features must be observed which are collectively responsible for the success of my process and enable strong brilliant dyeings to be made on wool and similar animal hairs with anthraquinone vat dyes of the character described, without undue attendant injury to the strength and character of the hairs. The critical features of my invention are (l) the use of salt, (2) the use of an eXcess of alkali metal hydrosulfite, and

(3) the maintenance of the dye bath at all times of an alkalinity corresponding to a pH between about 12 and about 13, i. e., suflicient to give a faint to considerable orange stain with Clayton yellowtest paper.

The use of salt and the excess of hydrosulfite are critical factors, and appear to contribute markedly'to the avoidance of deterioration in the tensile strength of the dyed material by the high alkalinity of the bath as well as to aid in the deposition of the dyestuff upon the animal hairs, although the mechanism of the protective action is not at all clear. However, I use a quantity of salt of at least about 5 grams per liter of dye liquor or sufiicient to provide at least about a .5% solution, as brought out above, and there should preferably be present an amount varying from 5 to 50 grams per liter on an anhydrous basis, depending upon the particular dyestuff and the strength of dyeing desired, the larger amount being used when darker shades are desired or when dyeing such vat dyestuffs which do not otherwise draw satisfactorily.

The salt should preferably all be added to the dye bath as originally prepared before the material to be dyed is entered, but in some cases it may be desirable to defer addition of part or all the salt until the dye bath has been brought to dyeing temperature. However, when such temperature has been reached, the salt concentration of the dye liquor should beat least about .5 or 5 grams of salt per liter. v

The alkalinity of the bath is important. The pH value of the vat, due to the presence of sodium hydroxide or its equivalent, used in my-process is higher than the pH values previously considered tolerable for use in wool dyeings, and is comparable to that customarily employed in dyeing cotton with the anthraquinone vat dyes. The amount and character of. alkali added to the dye bath in any specific case will be deter.- mined by the particular dyestuii used, the length of the dye bath, 1. e. the ratio of the volume of the dye liquor. to the weight of materialto be dyed, the temperature of the bath, dyeing time and the like as is well known in the art. However, regardless of the above variations, the amount of alkali present in the dye bath should be sufficient at all times to show a persistent faint to considerable color change with Clayton yellow test paper; that. is, to produce a pH value between about 12 and about 13. The test paper should not show the complete color change from yellow through orangeto red, characteristically produced on Clayton yellow test paper by solutions wherein pH is increased from about 12 to about 14, but should show at least a faint orange color but not more than a distinct orange color. Clayton yellow changes from a lemon yellow through orange to red at a true pH between about 12 andabout 14 regardless of the presence of excess alkali metal ions. It is therefore especially suitable for use in msting the pH of my dye baths, which contain an excess of alkali metal ions through the addition of salt, excess hydrosulfite, etc., since the apparent pH values as measured by certain glass electrode type pH meters tend to be unreliable for pH values above about 10 and will be radically altered by such excess alkali metal ions although the alkalinity may remain constant. Thus the true pH of my dye bath may vary between about 12 and about 13, whereas the apparent pH as read on a glass electrode type pH meter without applying the needed corrections may vary between about 10.8 and about 11.8.

The alkali used will preferably be made up primarily of an alkali metal hydroxide, but may be augmented or partially replaced by other alkalis such as trisodium phosphate, alkali silicates, alkali metal carbonates or the like, provided the total alkalinity is suiiicient to provide the pH range as measured by the orange color test described above.

2&983032 5 oa es. Where res de. 1 aci -is leftv the hair Pre u rocess n Su c mu "of. u ea eith r b n utra ize c d n h et beer the ua t o a a i se n h a be in ea by e ou t ne ssa to neutralize whatever acid is p esent in the material While h a lie i i of t e ye h a ry with-in the pH; range specified, the bath will usually-besomewhat more alkaline at the start of the dyeing than at the end. Usually the dye bath will e made up initially to show a distinct orange colors-hangs on Clayton yellow test paper, and the alkaline character of the bath should be maintained throughout the dyeing so that duringand :5

stiles e d o the e n i sh t ea a f i orange coloration with the Clayton yellow test ear-en The temperature of dye bath ,is usually maintained within a relatively much narrower range than for comparable cotton dyeings, namely, between about 90 F. and about 125 'F. regardless of the dyestuif used, preferably between about 100 F. and about 115 F. when the dyeingis carried out in conventional wool dyeing equipment; as compared to temperatures varying between about 70 and about 140 F., depending onthe dyestuffused, in the normal cotton dyeing process, The temperature used will depend somewhat on the dyeing time, a lower temperature requiring a, longer dyeing time, and on other conditions, as brought out below. The goods are preferably entered into the bath at about 90 ER, and-the temperature thereafter is raised to the dyeing temperature.

The time of dyeing will usually be at least about minutes, and usually varies between about 10 and about so minutes total time including the time required to bring the dye bath to the. dyeing temperature. The dyeing time will depend somewhat on the temperature as well as on other dyeing conditions, for example, dyeing times of from to 60 minutes are suitable at temperatures ranging from 90 to 125 Rfor dyeing in conventional wool dyeing equipment, whereas considerably shorter times will suffice, and higher temperatures may be used with suitable continuous high speed dyeing equipment.

A quantity of alkali metal hydrosulfite will be used as a constituent of my dye bath, as is customary in dyeing with anthraquinone vat dyestuffs The hydrosulfite reduces the dye to the leuco form and maintains it in the leuco state in the dye bath. However, the quantity of hydro-v sulf te used should not only be sufficient to perform this function, but should be substantially in excess of this amount and preferably should be. at least about equal to the amount of alkali metal hydroxide used in the bath. I have found that the use of an excess of alkali hydrosulfite contributes toward the protection of the woolv entering into the dye bath but, if desired, may be,

entered into the bath in the dry state, When this dry method used, the material should, in

case of constructions which, do not wet readily, such as flannel, be treated with a wetting agent and. should retain a sufiicient amount of wetting of an alkyl aryl sodium sulfonate about 60% of sodium sulfate.

Actual dyeing of the material according to my invention is carried out according to approved dyeing practice except for the modifications enumerated. The material is first scoured, then, if desired, treated with a wetting agent in any suitable manner, is entered into the dye bath,

brought to temperature and maintained at the desired temperature for the appropriate length of time. Before entering the goods to be dyed, the dye bath is made up with water, alkali, hydrosulfite, salt, reduced dyestuff and, if desired, a wetting agent such as sulfonated castor oil. The bath is tested with Clayton yellow test paper to assure a faint to appreciable orange reaction characteristic of Clayton yellow at pl-l values between about 12 and about 13. The Clayton yellow, or thiazole yellow test paper'used, is prepared as is well known, by impregnating filter paper with a 25% solution of thiazole yellow dye, Colour Index No. 813, and thereafter allowing it to dry, The test paper is sensitive to free alkali, turning from a lemon yellow through orange to red as the pl-I value progressively increases from about 12 to about 14.

The dye bath ratios used are those in common use, and these ratios dependon the materialbeing dyed and the depths of shade desired. and also Oil the type of equipment used as is well known. Thus the dye bath ratios may vary widely, for example from about 8:1 up to. about 60:1, but. preferably will range between about 10 :1 and 15:1' for closed type dyeing equipment, and between about 30:1 and 50:1 for open type dyeing equipment.

After the dye bath is prepared the goods are entered into the bath preferably at temperatures somewhat below the temperature of dyeing, for example between about and F. and are dyed at the temperatures and for the lengths of time indicated, above. After dyeing, the color may be developed by oxidation in any suitable manner asknown in the art.

Animal hairs dyed according to the process of my invention are not unduly deteriorated in tensile stren th over that exhibited by the undyed material; in fact, deterioration is often less than that; produced, by chrome dyeings and is usually less than that, caused by various, commonly used preliminaryv treatments, such as chlorination and other anti-shrinkage treatments, whereas wool fabric, dyed according to the, cotton process for dyeing anthraquinone vat dye colors, will exhibit losses in breaking strength so great as to render the fabric unfit for use.

The vat dye-stuffs which may be applied according to the process of my invention are those of the well known so-called anthraquinone vat dye stuffs, such as listed in Rowes Colour Index,

section XXIV, and especially those whose leuco form requires that the pH of the alkaline solution be above about 12 to maintain them in substantially complete solution. Examples-of a number of dyestuffs whose leuco form requires that the pH of the alkaline solution beabove about 12 to maintain them in substantially complete solution are given below with the Schultz Farbstofl fabellen numbers. Colour Index numbers, or "Prototype numbers:

Colour Schultz Index Number Number Anthraflavone G, GO 759 1,095 Oarbanthrene Golden Orange G 760 1,096 Oarbantlirene Golden Orange RRT 762 1,098 Oarbanthrene Dark Blue DR 763 1,099 Indanthi'ene Violet Rl 764 1, 100 Carbanthrene Brilliant Green 1, 101 Carbanthrene Black B, BS 765 l, 102 Oarbanthrene Violet R 766 1,103 Oarbanthrene Violet 2R 767 1,104 Indanthrene Violet B. 768 1,105 Oarbanthrene Blue RS 837 1,106 Carbanthrene Blue 3 G 840 l, 109 Indanthrene Blue 56. 844 l, 111 Indantlirene Blue OE 1,112 Oarbanthrene Blue GOD-G, GOD-R 842 1,113 Oarbanthrene Blue BOS, BCF 1, 114 Indanthrcne Blue GO 843 1,115 Indanthrene Green 2B 847 1,116 Carbanthrene Yellow G 849 1,118 Indauthrene Grey B. 848 1,123 Indanthrene Red G 826 1,140 Indanthrene Red R 830 1,142 Indanthrene Bordeaux 828 1,146 Iudanthrenc Brown GR. 873 1,1 19 Oarbanthrene Olive R. 833 1,150 Oarbanthrene Brown AR 1,151 Oarbanthrene Brown A G 1,152 Oarbanthrene Violet BN 832 1,163 Indanthrene Olive G 791 1,167 Cibanone Orange R 792 1,169 Cibanone Yellow R 795 1,170 Cibanone Blue 3G. 793 1,173

Prototypes A. A. 'l. C. C. Year Book 1946 Oarbanthrene Flavine GO 9 Oarbanthrene Brilliant Violet 4R. 117 Oarbanthrene Brown BR 1.18 'Oarbantlirene Brown GGA 119 Carbanthrene Khaki 2G. 122 Indanthi'cne Pink B 123 *Oarbanthrene Red G213 124 Carbanthrene Yellow Brown 3 G 125 lndanthrene Brilliant Orange GR 287 .Indanthrene Brilliant Violet 3B 288 Indanthrene Direct Black RB 289 (Jaidoanthrcne Golden Orange 3G. 290 Carbanthrene Olive Green 13 g. 293

Carbanthrcne Red FBB My process is adapted for use in any suitable known types of vat dyeing equipment, for example in either open or closed equipment. The dyes may be applied to the animal fibres in solution in standard vat dyeing equipment or they may be applied or padded as a pigment suspension or as a vat acid (Kuepensaeure) suspension as is well known in the dyeing art, and the goods may then be developed in a solution of caustic alkali together with hydrosul'fite and salt in a jig or other suitable equipment. If the dyes are to be padded by the vat acid process, 1. e. by the Kuepensaeure process, the dye is first dispersed in a solution containing water, an alkali and a dispersing agent such as a formaldehyde condensa- 8 tion product of naphthalene sulfonic acid (Tamol NNO), and then reduced to the leuco compound with alkali hydrosulfite and transformed to the vat acid with acetic acid, sulfuric acid, etc., as is well known. In the application to the goods of the dyestufis in pigment suspensions, the dye is applied (padded) at relatively high temperatures (140-160" F.) and is then developed or fixed at the lower temperatures indicated, in a bath similar to those described for solution dyeing except for the absence of dyestuif. The concentrations of materials as well as times and temperatures in the developing bath are similar to those recommended for the dye bath dyeings previously described.

The following specific examples will further serve to illustrate my invention:

Example 1.-Anthraquinone vat-dyeings were made on all wool flannel as follows:

Weight of materialapprox. 9 oz. per yard (based on 56" width).

Warpworsted yarn.

Filling-W001 yarn.

Two strips A and B of the above flannel, 15 yards long and 6 inches wide, weighing 425 grams, were treated with 3% of an alkyl aryl sulfonate wetting agent (Nacconol NR) and 0.7% ammonia (26%) for 20 minutes at F., extracted and dried. (This material is referred to as scoured only) Strip A was wound full width around the perforated shaft of a 1 lb. laboratory package-dyeing machine, and was then dyed with Carbanthrene Blue GCD-G double paste (0. I. 1113) under the conditions listed under A, Conventional process in the table below. The alkalinity of the dye bath was such that an orange coloration characteristic of a true pH between about 12 and about 13 was obtained when the dye liquor was tested with Clayton yellow test paper. After dyeing and rinsing with cold and hot water, the cloth was removed from the machine and, in rope form, rinsed at F. in a liquor containing 4 grams alkyl aryl sulfonate wetting agent per liter.

Strip B was handled as A but was colored as given in the table below under B, Novel process."

The tensile strengths of both warp and filling of the dyed strips A and 33 as well as on the scoured only material were determined on a Scott tester, and are also listed in the following table. The value recorded is the number of pounds pull required to break the goods, and thus a low value denotes a low strength, a high value a high strength. The increase in tensile strength of strip B over the undyed scoured only material is believed to be due to a slight degree of felting which takes place in the vat dyeing process.

Vat dyeings of wool flannel with carbanthrene blue GCD-G-Double paste Material Scourcd Material dyed under the following conditions:

only

A-Oonventional Process for cotton B-Novcl Process Dyestuif used Caustic soda, NaOH, dry

Sodium hydrosulfite Cone.

8% Garb. Blue GOD-G Double Paste. 4.8 gins. per liter (4 lbs. per 100 gal).-. 3.6 gins. per liter (3 lbs. per 100 gal.)

Common salt, NaOl none 30 gms. per liter (25 lbs. per 100 gal).

Alkalinity. orange to Clayton yellow paper. light orange to Clayton yellow paper.

Time of dyeing. 30 minutes 20 minutes.

Temperature F stagtletd F. heated to 105 1 run 10' Rinses after dyeing 15 min. in cold water, 10 min. in hot 15 min. in cold water, 10 min. in hot water water Vat dyeings of 'wool flannel with carbanthrene blue Gefl-eG -Double paste-Continued 1 Materialdyed underthelollowingconditions:

Scdllfgd r r 7 only fn fionventional P'roces "1hr cotton "BNovelProcess Results:

Shade and strength lair shade and strength lull shade of Royal Blue, much brighter and richer than A Feel-oi material soft. harsh and cottony"- solt woolly" touch Resistance'to tearing (by hand) g'ood poor, appearsverytender good. Tensile strength per :in'ch (Scott Tester) (average of tests): v Warp. 39.5lbs. 35.0 lbs; 42.0 lbs. (20% strongerthan A)'. Fillin 27.2lhs 1 17. 2 lbs f 28.0'1bs.(63% stronger than A).

Eztample 2.--To 1.0 gram of Carbanthrene Blue GCD-G Double Paste/C; I. 1113', were'a-dded 0.4 ml. 'Sulion'ated castor oil. 90.0 ml.Water at 150 F.

10.0 ml. Caustic soda (of a solution by volume, Le. 10 grams NaOH per 100 cc. of solution).

Approx. 100 ml. at 140 1*.

64.0.0 m1. Water. I p

25.0 ml. Common salt (of a solution by volume, i. e.

20 grams of salt per 100 ml. of salt solution). 8.0 ml. NaOH 10% by volume. 2.6 gm. Hydro.

Approx. 675.0 m1.

100.0 m1. Stock vat as prepared above.

775.0 m1. at 100 F.

The dye bath was then tested with Clayton yellow test paper and found to produce an orange colora- .tionon the paper. Then 20 grams of a light weight (5 /2 oz. per yard, 56 wide) worsted ma- .terial, lightly chlorinated, were prepared with an alkyl .aryl sulfonate wetting agent and ammonia, as described above and dyed in the above liquor (a 40:1 dye bath ratio) as follows:

The material was entered dry, worked for 5 minutes at 100 F. when an'addition of ml. of a 20% solution of NaCl was made and the cloth worked for another 5 minutes. The temperature was then raised to- 110 F. within 10 minutes, and the dyeingcontinued at this temperature for an additional 10 minutes. The goods were then passed through squeeze rollers, aired for 10 minutes, rinsed well with cold Water until free of alkali. The oxidation was completed by a treatment for 15 minutes in a bath containing 3% potassium persulfate, starting at 110 F. and raising the temperature gradually to 140 F. The material was then soured with 10% sulfuric acid .for 10 minutes at 180? F., rinsed twice with warm water, followed by a treatment for .15 minutes at 140 F. in a bath containing 2 grams Nacconol 5% Color paste p 2% Turkey red oil (sulfonted castor oil) 9%"Caustic soda (dry) '10 Hydro 50%"Common Salt (NaCl) Alev'el dyeing was obtained of good penetration: and of a depth at least equal to a 5% dyeing of the same eolor on cotton. The tensile strength oft'he cloth, both'inwarp and filling was'found to bepractically equal to the breaking Strength of Y the undyed material.

Example 3.20 grams of cloth, identical with the material usedin Example 2,-were dyed with:

5.0% Car banthrene Flavine GC Double Paste (Prototype 9) 2.0% Turkey red oil 7.5% Caustic soda 15.0% Hydro 50.0% Common salt (lr'oto'type 291) 0. 4 ml. Turkey red oil 90.0 ml. Water 10.0 ml. NaOH, 10% solution Approx. 100.0 ml. at 140F. Add 1.0 gm. Hydro, reduce 10 minutes at 140 F. and pour into dye bath made up as follows: 620.0 ml. Water I 30.0 ml. Trisodium phosphate (Na3PO4.12H20), 10%

solution 50. 0 ml. Common salt 20% solution 2.0 gm. Hydro (100.0 m1. Stock vat) Approx. 800. 0 ml.

Material was worked at F. for 10 minutes, the bath was then heated within 5 minutes to F. and the dyeing continued for another 15 minutes at 110 F. Shade was developed as in Example 2. The composition of the dye bath in Example 4 is:

5% Dyestuff paste 2% Turkey red oil 5 Caustic soda 15% Trisodium phosphate crystals (NasPO&.- 12Hz0) 15%Hyd'ro I 50% Common salt A full shade of a golden yellow color was obtained. at, least equal in depth to a 5% dyeing of the same dyestuff on cotton and of similar fastness properties, and having a tensile strength only slightly below that of the undyedcloth.

Example 5.-(Pigment Pad-Jig Process): A 35 gram strip of densely woven worsted cloth weighing 12 oz.,per yard, previously prepared with wettingf agent as explained above, was padded at F. with a liquor containing 100 grams per liter of Carbanthrene Golden Orange RRT Grains, a very finely dispersed form of Carbanthrene Golden Orange RRT, C. I. 1098.

The padded cloth was treated as'desoribed in previousexamples in full width for 30 minutes at "110PF.-120 F. in 700 ml. of a developing bath containing 2.8 grams of "NaOI-I, 5;6 grams of Hydro and 17.5 grams of NaCl. It was then approx. 236 ml.

passed through squeeze'roller'sand' flr iis h ed as described in Example 2. A full shade of orange of fairly good penetrationand "good-tensile strength was obtained.

Example 6. (Kuepensaeure Pad-"Jig Process) A pad liquor containing 80 grams of Carbanthrene Blue GCD-G Double Paste prepared as follows:

Oarbanthrene Blue GOD-G Double Paste Water gm. 170 ml. 16 ml.

tion by volume NaOH (10% solution) at 140 F. p Hydro, reduce l0 minutes add Acetic acid 28% with vigorous stirring Vat acid pad liquor Add 2. 4 gm.

Approx. 250.0 ml.

A gram strip of worsted cloth, as used. in Example 5, was padded at 140 F. with the above vat acid suspension and was. then developed as given in Example 5. A full shade of blue of good penetration was obtained with no undue reduc} Apgrox. ml. at 140 F.

4 gm. Hydro, reduce 10 minutes, acid, with vigorous, stirring. 23 I11]. Acetic acid 28% previously diluted with 77 ml. Hot water.

Approx. 500 ml. Vat acid pad liquor Material padded at 140 F. and treatedin full width for minutes at 120 F. in a developing bath containing 1 300 m1. Water 0.6 gm. NaOH 1.2 gm. Hydro and 7.5 gm. NaCl 2% Carbanthrene Blue GCD-G Double Paste 2% Turkey red oil 9% Caustic soda 18% Hydro 30% Common salt The raw wool was worked very gentl'yin order to prevent undue felting. The shade, was developed as given in Example 2. A dyeing'was' produced which shows the tippy nature of the material to a lesser degree than do dyeings of Alizarine Acid colors made on the same stock. Example 9.--10 grams of tlppy mohair raw stock, previously prepared with a wetting agent 'of'110 FL-120 F.,'ratio 40:1, in a bath containing:

"5% Carbanthrene Blue GOD-G Double Paste (o. I. 1113) per liter, in form of its'leuco acid was Tamol NNO-disp'ersingagent. ota solu as explained above, were dyed-01120 minutes as described in previous examples at a temperature 2% Turkey red oil 9% Caustic soda 18% Hydro 50% Common salt and were then finished as in Example 2. A dyeing which was equal in depth to a 5% dyeing of Carbanthrene Blue GCD-G Double Paste on cotton was obtained.

1 Example 10.-10 grams of combed sliver, in skein form, were dyed for 30 minutes at F.- F., ratio 40: 1, in abath made up as shown in Example 4, and containing:

5% Carbanthrene Brown-AR Double Paste (C. I. 115.l.).-

2% Turkey red oil 5% caustic soda 15% Trisodium phosphate crystals 1 H d o 60% Common salt Oxidized as in Example 2. A bright brown dyeing of outstanding fastness was obtained.

Example 111-10 grams of rabbits fur were dyed-for 25 minutes at 105 F.-l20 F., ratio 40:1, in a bath made up with:

5% Carbanthrene Olive R Double Paste (C. I.

2 Turkey red oil 10% Caustic soda 15% Hydro 80% Common salt Oxidized as in Example 2. An olive drab dyeing of outstanding fastness was produced on the fur, ofa depth of shade which is about half the depth obtained on wool with the same amount of dyestuff.

5 Carhanthrene Blue GCD-G Double Paste 2% Turkey red oil 9% Caustic soda 18 Hydro 80% common salt Finished as given in Example 2. A full shade of a bright blue of outstanding fastness properties and good tensile strength was obtained.

My process makes it possible to obtain colored efiects on animal hairs with a degree of fastness and brilliancy of shade hitherto unknown on this type of fiber. lhus, a dyeing produced with 2% Carbanthrene Blue GCD-G Double Paste, Color Index 1113, was found to exhibit a lesser degree of fading after 240 hours fadeometer exposure than do dyeings of similar shade and intensity obtained with fast-to-light acid colors (such as Alizarine Sapphire, C. 1'. 1054 or Alizarine Blue GRL Extra, 0. I. 1088) after only 60 hours exposure. Furthermore, dyeings on wool made with C'arbanthrene Blue GOD-'G are very much faster to washing than are colorings obtained with the anthraquinone acid dyes, and are faster to washing than dyeings made with acid milling colors. Compared with colorings produced on wool with chrome colors, or with metallized acid dyes, dye;

ings obtained with vat dyes according to my process show considerably greater brilliancy, superior fastness to light and equal or superior wash fastness. A dyeing made with Carbanthrene Brown AR was practically unchanged after 400 hours fadeometer exposure, while a similar shade produced with some of the fastest chrome dyes shows a considerable break after 120 hours, and is very badly faded after 400 hours.

While the above describes the preferred embodiments of my invention, it will be understood that departures may be made therefrom within the scope of the specification and claims.

I claim:

1. In a process for dyeing animal hairs with anthraquinone vat dyestuffs in reduced, alkaline vats, the step which comprises carrying out the dyeing in an anthraquinone vat liquor containing an alkali, an alkali metal hydrosulfite in an amount between about 1 and about 2 times the amount by weight of the alkali in the liquor, and a quantity of a neutral alkali metal salt between about 5 and about 50 grams per liter of vat liquor, while maintaining the vat at all times during the dyeing sufficiently alkaline to produce a slight to considerable color reaction with Clayton yellow test paper, and at temperatures between about 90 F. and about 125 F.

2. In a process for dyeing animal hairs with anthraquinone vat dyestuffs in reduced, alkaline vats, the step which comprises carrying out the dyeing in an anthraquinone vat liquor containing an alkali, an alkali metal hydrosulfite in an amount between about 1 and about 2 times the amount by weight of the alkali in the liquor, and a quantity of a neutral alkali metal salt between about 5 and about 50 grams per liter of vat liquor, While maintaining the vat at all times during the dyeing at a pH value between about 12 and about 13, and at temperatures between about 90 F. and about 125 F.

3. In a process for dyeing wool with anthraquinone vat dyestuffs of such character that they are substantially completely soluble in aqueous alkaline solutions only at pH values above about 12, the steps which comprise carrying out the dyeing at temperatures between about 90 F. and about 125 F. in an alkaline vat containing the dyestuff, an alkali metal hydroxide, an alkali metal hydrosulfite in an amount equal to between about 1 and 2 /2 times the amount by weight of the alkali metal hydroxide, and between about 5 and about 50 grams per liter of sodium chloride, while maintaining the pH of the vat liquor at all times at a pH value between about 12 and about 13.

4. In a process for dyeing animal hairs with anthraquinone vat dyestuffs, the steps which comprise preparing a vat liquor containing the dyestuff, suflicient alkali to maintain the liquor at all times during the dyeing at an alkalinity sufficient to produce a slight to considerable orange color reaction with Clayton yellow test paper, a quantity of an alkali metal hydrosulfite equal to between about 1 and 2 times the weight of the alkali used, and a quantity of a neutral alkali metal salt equal to between about 5 and about 50 grams per liter of liquor; and carrying out the dyeing for periods between about 15 and about minutes at temperatures between about F. and about F.

5. The process of claim 4 wherein the salt used is sodium chloride.

6. The process of claim 4 wherein the salt is sodium sulfate.

'7. The process of claim 4, wherein the animal hairs are wool.

8. In a process for dyeing animal hairs with anthraquinone vat dyestuffs, the steps which comprise preparing a vat liquor containing the dyestuif, sufficient sodium hydroxide to maintain the liquor at all times during the dyeing at an alkalinity sumcient to produce a slight to considerable orange color reaction with Clayton yellow test paper, a quantity of sodium hydrosulfite equal to between about 1 and 2 /2 times the weight of the sodium hydroxide used, and a quantity of a neutral sodium salt equal to between about 5 and about 50 grams per liter of liquor, and carrying out the dyeing for periods between about 15 and about 60 minutes at temperatures between about 90 F. and about 125 F.

9. The process of claim 8, wherein the animal hairs are wool.

ARTHUR E. WEBER.

REFERENCES CITED The following references are of record in the file of this patent:

FOREIGN PATENTS Number Country Date 466,810 Germany Oct. 11, 1928 390,513 Great Britain Apr. 5, 1933 OTHER REFERENCES Technical Bulletin of du Pont de Nemours 8: 00., Wilmington, Del., vol. 4, No. 2, for June 1948, pages 53-56.

Vat Dyeing of Wool, by S. J. Luscian, Calco Tech. Bulletin No. 797, published by Calco Chem. Div. of Amer. Cyan. Co., of Bound Brook, N. J.. published October 1947, pages 2-4. 

1. IN A PROCESS FOR DYEING ANIMAL HAIRS WITH ANTHRAQUINONE VAT DYESTUFFS IN REDUCED, ALKALINE VATS, THE STEP WHICH COMPRISES CARRYING OUT THE DYEING IN AN ANTHRAQUINONE VAT LIQUOR CONTAINING AN AIKALI, AN ALKALI METAL HYDROSULFITE IN AN AMOUNT BETWEEN ABOUT 1 AND ABOUT 2 1/2 TIMES THE AMOUNT BY WEIGHT OF THE ALKALI IN THE LIQUOR, AND A QUANTITY OF A NEUTRAL ALKALI METAL SALT BETWEEN ABOUT 5 AND ABOUT 50 GRAMS PER LITER OF VAT LIQUOR, WHILE MAINTAINING THE VAT AT ALL TIMES DURING THE DYEING SUFFICIENTLY ALKALINE TO PRODUCE A SLIGHT TO CONSIDERABLE COLOR REACTION WITH CLAYTON YELLOW TEST PAPER, AND AT TEMPERATURES BETWEEN ABOUT 90*F. AND ABOUT 125*F. 